RJC Rasayan J. Chem. Vol.1, No.4 (2008),795-801 STUDIES ON ENTEROCOCCUS FAECIUM GROWTH - INHIBITORY ACTION OF 1,5-BIS (2-HYDROXYPHENYL)PENT-1,4-DIENE-3-ONE AND RELATED COMPOUNDS: A SEARCH FOR ENVIRONMENTALLY BENIGN ANTI-BACTERIAL AGENT Archna Rani * and Sapna Jain Department of Applied Chemistry, Delhi College of Engg., University of Delhi, Delhi-110042, India. E-mail: archna.rani@gmail.com ABSTRACT Following the basic concept of Green chemistry the present work is aimed at synthesis of compounds and evaluating their antibacterial action against clinically isolated resistant pathogenic strain of Enterococcus faecium.Thus a conjugated carbonyl compound, (1a; 1, 5-bis(2-hydroxyphenyl)pent-1,4-diene-3-one) was synthesized as a representative compound by incorporating reported basic bioactive chemical moieties and various transformations in the structure has also been made, as, absence of hydroxyl group (2a;1,5-Diphenylpent-1,4-diene- 3-one), extension of conjugation (3a;1,9-Diphenylnon-1,3,6,8-tetraene-5-one), introduction of dimethyl amino group (4a;1,5-bis[4-(N,Ndimethyl)phenyl] pent-1,4-diene-3-one), replacement of benzene ring with heteroaromatic ring (5a;1,5-difuranpent-1,4-diene-3-one). All the compounds were screened for the first time against E.faecium. In preliminary test 1a exhibited encouraging result, it was therefore further studied for bacteriostatic action by turbidimetric kinetic methods. Growth kinetic curves of E.faecium were made in nutritive broth added with increasing concentration of the compound .Its Minimum Inhibitory Concentration (65μg ml -1 ) was evaluated graphically. The activity of 1a was found to correlate with its structural resemblance with chalcones, presence of conjugated carbonyl group and presence of hydroxyl group at 2 and 2’on the benzene ring. In the absence of hydroxyl group, only increase in number of double bonds (3a) is not essential in eliciting the activity but associated with increasing it. Compound 1a may be of great interest due to its bacteriostatic property as well as its synthesis by straight forward reaction at room temperature. Keywords: Conjugated carbonyl compounds, chalcones, E.faecium, bacteriostatic action, antibacterial agent. INTRODUCTION In the present time, a wide variety of chemicals are being used to control infectious diseases. But their hazardous nature, use of harmful chemicals as catalysts and solvents for their synthesis, are of prime concern for environmentalists. Also development of rapid resistance in pathogenic microbes is emerging out as a serious problem before the biologists.Thus designing of environmentally benign potential antimicrobial agent is a pressing need of today and is still a challenge before the scientists, worldwide. As a result the compounds of natural origin and their derivatives are getting intense interest of the researchers worldwide for development of new class of eco-friendly antimicrobial agents. Flavanoids, in this regard, have attracted considerable attention as they possess a wide range of biological activities 1-3 , such as antimicrobial 4-7 , antiviral 8,9 , anti-inflammatory 10,11 , bactericidal and bacteriostatic action 12 and other therapeutic applications 13 . Chalcones, a type of flavanoids, in particular, are studied exhaustively by many scientists 14-16 for their antimicrobial effect. Also in various independent investigations it has been observed that cinnamic acid and its derivatives 17 and compounds having carbonyl group in conjugation with double bonds exhibit various biological activities 18 . Keeping all these points in view an attempt has been made in the present work to design a compound incorporating the above mentioned parameters in the basic structure of chalcone moiety (A). Thus 1, 5-bis (2-hydroxyphenyl)pent-1,4-diene-3-one), (1a), was synthesized as a Studies on Enterococcus faecium Archna Rani and Sapna Jain 795